Search found 517 matches

by VK3QI
Fri Apr 03, 2020 3:15 pm
Forum: 1296, Microwaves and Opto
Topic: 5.7 GHz transverter - finished (finally)
Replies: 3
Views: 51

Re: 5.7 GHz transverter - finished (finally)

Peter,

Looking at your pictures, it appears that you are using about 4 metres of blue jacket RG402 for the TX feed line. Is that correct? Have you considered the loss in that length of cable on the 10watts from the amplifier?

Cheers

Peter VK3QI
by VK3QI
Wed Jan 22, 2020 11:47 am
Forum: Ancillary, Test Equipment, Components & Parts
Topic: HP Agilent 53131A 53132A 53181A 12.4 GHz option
Replies: 4
Views: 564

Re: HP Agilent 53131A 53132A 53181A 12.4 GHz option

Adam, Why not look for a good secondhand HP5350B counter? That will get you to 20GHz. They sometimes come up at auction or where a business has closed down, for quite reasonably comparable prices to the latest offerings from China and Europe. The unit is bulky compared with the more modern units, bu...
by VK3QI
Fri Dec 20, 2019 8:12 am
Forum: Ancillary, Test Equipment, Components & Parts
Topic: Kings Generators
Replies: 14
Views: 1877

Re: Kings Generators

Compton, Your observation highlights an issue with the "ECO" operation of the Honda generators. When trying to start appliances like an air conditioner, which has a high start current, the Honda needs to be in the operation mode with the "ECO" switch off, so that the engine revs are sufficient to ab...
by VK3QI
Wed Dec 18, 2019 9:18 am
Forum: Ancillary, Test Equipment, Components & Parts
Topic: Kings Generators
Replies: 14
Views: 1877

Re: Kings Generators

Hayden, You ask for specific details about filtering for Honda generators. I own 2 EU10s, 1 EU20 and 1 EU22 and have replaced my first EU20 (circa 2002 with over 1200 hours)- although that generator is still doing service with the VK3KQ/p team. When the Honda generators first came on the scene, myse...
by VK3QI
Tue Nov 26, 2019 4:33 pm
Forum: 1296, Microwaves and Opto
Topic: 47GHz 76GHz enthusiasts
Replies: 4
Views: 882

Re: 47GHz 76GHz enthusiasts

Gary,

There was a recording made. I do not have the details, however an email to David VK5KK should find what availability the video will have.

david@vk5kk.com


Cheers

Peter VK3QI
by VK3QI
Wed Nov 13, 2019 9:59 am
Forum: 1296, Microwaves and Opto
Topic: Inside the RF HamDesign feed
Replies: 6
Views: 902

Re: Inside the RF HamDesign feed

As a long time successful user of RF HAMDESIGN 1/2 Dual Band, 3/5/10 Triband and 1/2/3/5/10 5 band feeds I would like to make a few points. (1) Moisture issues can be alleviated by simply drilling a drain hole in the bottom of the feed. I note the LA boys were using a Gore-Tex plug, no doubt to stop...
by VK3QI
Sat Nov 09, 2019 12:36 pm
Forum: 1296, Microwaves and Opto
Topic: 47GHz 76GHz enthusiasts
Replies: 4
Views: 882

47GHz 76GHz enthusiasts

Friday 15th November Meeting with OE amateurs. The following has been circulated - maybe some on the logger forum may have missed it. Microwave Show and Tell We are pleased to welcome Wolfgang OE4WOG and Hans OE2JOM to our monthly clubroom meeting where they will discuss their activities, achievemen...
by VK3QI
Fri Oct 11, 2019 10:08 am
Forum: Ancillary, Test Equipment, Components & Parts
Topic: BG7TBL GPSDO (GPS Disciplined Oscillator) and 10 MHz Distribution Amplifier
Replies: 4
Views: 2106

Re: BG7TBL GPSDO (GPS Disciplined Oscillator) and 10 MHz Distribution Amplifier

Adam and Hayden, Just to reinforce the information about the warble. I was referring to the BG7 10 Mhz distribution amplifier r with in-built OCXO, NOT the 10 Mhz GPS unit. If you look at the comments that followed that posting, the discussion reverted back to the GPS unit. I have had nothing but gr...
by VK3QI
Wed Sep 04, 2019 11:23 pm
Forum: Transceivers, Transmitters & Receivers
Topic: Icom IC-705 new QRP SDR HF-70cm backpack rig (pre-release info)
Replies: 5
Views: 2109

Re: Icom IC-705 new QRP SDR HF-70cm backpack rig (pre-release info)

Adam, Spot on regarding the proposed IC-705. I have a couple of 817ND units for various 24 and 47 Ghz transverters and by far the best thing that can be done for an 817 is to add DSP in the form of the BHI units. I have already added the TCXO units. I have often wondered why the 818 upgrade didn't i...
by VK3QI
Wed Sep 04, 2019 11:03 pm
Forum: 1296, Microwaves and Opto
Topic: Live stream from REAST - Talking microwaves
Replies: 2
Views: 1812

Re: Live stream from REAST - Talking microwaves

FACT CHECK - the 817 weighs 1.17 Kg including the battery but excluding the mike - certainly not 3Kg as claimed in the video.

Peter VK3QI
by VK3QI
Wed Sep 04, 2019 2:19 pm
Forum: Transceivers, Transmitters & Receivers
Topic: Icom IC-705 new QRP SDR HF-70cm backpack rig (pre-release info)
Replies: 5
Views: 2109

Re: Icom IC-705 new QRP SDR HF-70cm backpack rig (pre-release info)

Nik, I'd be holding off on any judgements until the rig actually sees the light of day sometime in 2020. Not an auspicious start, when it is advertised as an SDR HF-70cm rig (until you read the fine print, where it says that 50, 144 and 432 are actually Hetrodyne conversion down to below 25 Mhz). Al...
by VK3QI
Sun Sep 01, 2019 9:20 am
Forum: 1296, Microwaves and Opto
Topic: Antennas for 3.4 GHz
Replies: 29
Views: 10046

Re: Antennas for 3.4 GHz

Hatden,

is this what you are looking for?

http://www.w1ghz.org/antbook/conf/WA5VJB_LPA_feed.pdf

Cheers

Peter VK3QI
by VK3QI
Wed Aug 28, 2019 11:13 pm
Forum: 1296, Microwaves and Opto
Topic: 2.4 GHz contact in Southern Tasmania over mountains
Replies: 9
Views: 5081

Re: 2.4 GHz contact in Southern Tasmania over mountains

Hayden, There are few tests you can do. (1) rotate the antenna in the horizontal and see what the beam width is (2) see if there are any lobes - these will be evident if the feed is not quite in the correct position (3) move the LP in and out to try and minimise any lobes - anything better than -20d...
by VK3QI
Wed Aug 07, 2019 1:34 am
Forum: 1296, Microwaves and Opto
Topic: Antennas for 3.4 GHz
Replies: 29
Views: 10046

Re: Antennas for 3.4 GHz

Hayden, You asked about the position of the focal point. If you go with the LP style of antenna, then the following reference is well worth studying. https://www.wa5vjb.com/references/DesigningPCB-LPs.pdf The section on phase centre will determine the position of the LP. Generally, you place the LP ...
by VK3QI
Wed Aug 07, 2019 1:24 am
Forum: 1296, Microwaves and Opto
Topic: Antennas for 3.4 GHz
Replies: 29
Views: 10046

Re: Antennas for 3.4 GHz

Iain, A bit of a Dorothy Dixer. Many hams think that the bi-quad should be horizontal for horizontal polarisation, when in fact polarisation is at 90 degrees to the bi-quads. Hayden had earlier questioned as to whether the 2.4 Ghz grid would be too wide for 3.4GHz. - the main thing is to get the gri...
by VK3QI
Tue Aug 06, 2019 3:33 pm
Forum: 1296, Microwaves and Opto
Topic: Antennas for 3.4 GHz
Replies: 29
Views: 10046

Re: Antennas for 3.4 GHz

Iain,

In your picture of the bi-quad, shouldn't the parabolic reflector be turned 90 degrees to have the bars horizontal?

Or is the bi-quad orientation incorrect?

Cheers

Peter VK3QI
by VK3QI
Tue Jul 16, 2019 12:28 am
Forum: Transceivers, Transmitters & Receivers
Topic: Icom IC-9700 users topic
Replies: 165
Views: 44043

Re: Icom IC-9700 users topic

Adam, I think there might be more "smarts" than that shown in that circuit diagram. I don't have access to the HM-219 but other mikes in the series also have similar PTT switching - which in reality is just a switched line to earth. Maybe the smarts are associated with the input circuit board in the...
by VK3QI
Mon Jul 15, 2019 9:35 pm
Forum: Transceivers, Transmitters & Receivers
Topic: Icom IC-9700 users topic
Replies: 165
Views: 44043

Re: Icom IC-9700 users topic

Adam,

Here is a link to the circuit diagram.

http://www.g4izh.co.uk/microphone-input ... ement.html

Scroll down about half way.

I presume that the diode must act as some sort of spike shunt, coupled with the low Q of the shunted 10n capacitor.

Cheers

Peter VK3QI
by VK3QI
Fri Jul 05, 2019 4:26 pm
Forum: Satellites & Balloons
Topic: Satellite ops with IC-9700
Replies: 7
Views: 5626

Re: Satellite ops with IC-9700

Adam, Just another example of where the TS2000 with its individual band PTT outputs has it all over the Icom rigs. The matter is now worse than ever. In previous Icom models, you had the ability to use the VSEND setting to UHF, which meant you could set the VSEND to 70cm. and 23cm. and the HSEND to ...
by VK3QI
Sat Jun 22, 2019 10:14 am
Forum: 1296, Microwaves and Opto
Topic: GPSDO Phase noise
Replies: 13
Views: 6405

Re: GPSDO Phase noise and BG7TBL distribution amplifer

Dave, Although not exactly related to what we were discussing before, I came across an interesting effect yesterday whilst setting up a rover station. I was using one of the GPS units previously discussed feeding into a BG7TBL 8 port distribution amplifier with an in-built OXCO as a backup. I alread...